Electric switch.



H. E. WHHE.

ELECTRIC SWITCH.

APPLICATION mu) JAN.22. 1914 3 SHEETSSHEET I.

Patented Aug. 14, 1917.

ATTORNEY Harald [.Whita. INVENTOB WITNESSES. QM. Q. QM

H. E. WHITE.

ELECTRIC SWITCH.

APPLICATION FILED IAN. 22, 1914. 1,236,520. Patented Aug. 14,1917.

I I 3 SHEETS-SHEET o FF ATTORNEY H. 1E. WHITE. ELECTRIC SWiTCH.

APPLICATION FILED JAN. 22. 1914. 1,236,520. Patented Aug. 14,1917.

3 SHEETS-SHEET 3.

.WITNESSE LAM. a. QM

ATTORNEY F15 5 HnruHLWHTaJNvI-imm UNITED STATES PATENT OFFICE.

HAROLD E. WHITE, 01? GLEN RIDGE, NEW JERSEY, ASSIGNOR TO CROCKER-WHEELERCOMPANY, OF AMPERE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ELECTRIC SWITCH.

Specification of Letters Patent.

Patented Aug. 14, 1917.

Application filed January 22, 1914. Serial No. 813,622.

To all whom it may concern:

Be it known that I, HAROLD E. WHITE, a citizen of the United States,residing at Glen Ridge, in the county of Essex and State of New Jersey,have invented certain new and useful Improvements in Electric Switches,of which the following is a specification.

My invention relates to electric switches in general, but moreparticularly to those employed to open and close or control the circuitsand connections of electric motors or other electrical machinery orapparatus. The object of my invention is to make such switches reliableand convenient in their action. To this end my invention consists ofcertain forms and arrangements of the elec trical contact making partsand connections as well as of the mechanical parts. These mechanicalparts or means employed to operate my switches are shown and described,for the sake of completeness, but are not claimed herein because theyare made the subject matter of my divisional application having the sametitle and original date of filing as the present application.

The accompanying drawings illustrate the construction and operation oftypical examples of my switches. Figures 1, 2 and 3 are perspectiveviews of an elementary form of switch embodying some of the features ofmy invention. The electrical connections of the switch shown in Figs. 1,2 and 3 are diagrammatically represented in Fig. 1. Figs. 5 and 6 showthe side motion or sliding of the contacts which may be obtained by myconstruction. Fig. 7 is a section and Fig. 8 a plan view showing some ofthe mechanical features of my switches. Fig. 9 is a section of a form ofmy switch.

The particular purpose of the simple form of my switch shown in Figs. 1,2 and 3 is to start, stop and reverse the direction of rotation of athree-phase motor by controlling the connection of its three terminalsto the three supply lines.

The corresponding electrical connections are indicated diagrammaticallyin Fig. 4. In Fig. 1 the switch is represented in its off position, thatis, the electrical connections are broken. My switch in this casecomprises the stationary elements 1, 2 which may be a board of wood orother suitable material provided with electrical contact making parts 3,4 5, 6, 7 and 8. These contacts may be pieces of copper or otherconducting material fixed in or upon board 1, 2. The movable element 9,10 may also be a board of wood or other suitable material mounted on therod 11, which is carried by the crank 14 that is attached to therotatable shaft 15 operated by the handle 16. The movable element 9, 10carries electrical contact making parts 17, 18, 19 and 20 which mayconsist of cylindrical studs of copper or other material. Preferably theconstruction is such that these studs are movable in and out of theboard a little distance and tend to be forced toward the stationaryelement 1, 2 by spring pressure. This pressure may be convenientlyobtained from helical springs 21 and 22 shown in Figs. 5 and 6surrounding portions of the studs of reduced diameter. In the positionrepresented in Fig. 1 the movable element 9, 10 is at its maximumdistance from the stationary element 1, 2 and the contact making partsof the former are sufficiently separated from those of the latter tobreak effectively any electrical connection between the two sets. Themovable element 9, 10 is guided by the swinging arm 12, 13 so that itremains parallel to the stationary element 1, 2 as it is moved from sideto side by the handle 16 and crank 1 1.

In Fig. 2 the movable element 9, 10 is represented as thrown to theright in which position its contacts 17, 18, 19 and 20 are pressedagainst the contacts 4:, 5, 7 and 8 respectively, of the stationaryelement, thereby establishing electrical connection between the twosets. Moreover these electrical connections are most effective becausethere is a certain amount of sliding motion between each movable contactand the corresponding stationary contact. This sliding motion is due tothe side swing of the element 9, 10 and occurs while the moving contactsare being forced a little distance against the spring pressuredescribed. The cause of this sliding motion is shown by comparing Figs.5 and 6. In Fig. 5 the contacts 17 and 18 carried by the element 9, 10are just beginning to touch those on the stationary element 1, 2. Thefurther movement of the element 9, 10 into the position indicated inFig. 6 has the efiect of sliding the faces of the contact studs 17 and18 on the contacts 4: and 5 respectively, at the same time forcing thestuds in and compressing the helical springs 21 and 22 as represented.One of the advantages that is obtained by the arrangement of the partsin this particular form of my switch is the fact that the contactsurfaces are vertical. Hence any dirt or any particles of metal due towear or fusion will fall away freely from both of said surfaces so thatthey can be brought together to make a good electrical connection. Withhorizontal contact sur faces, such extraneous matter tends to remain andcollect on the lower one which prevents or interferes with the making ofa proper electrical connection. If the board 9, 10 is thrown to the leftby means of the handle 16 the connections of two of the supply lines Band C with the motor terminals E and F are reversed. This, of course,causes the motor to run in the opposite direction. The electricalconnections are shown in Fig. 4, the circles 3, 4, 5, 6, 7, and 8representing the contacts on the fixed element 1, 2, and the squares 17,18, 19 and 20 representing the contacts on the movable element 9, 10. Inthis particular case the contacts 17 and 18 are connected together by aconductor 23, and the contacts 19 and 20 are connected by a conductor24.

Some of the mechanical features of my switch shown in section in Fig. 7and in plan in Fig. 8 are applicable to those uses for which it isdesirable to insure the movement of the switch in one direction from aneutral position before it is in condition to be moved in the otherdirection. For example, in controlling an induction motor it isimportant to make sure that the movable contacts are thrown to the rightin order to connect the primary windings in star relation for start ingbefore these contacts are thrown to the left to make the deltaconnections for running. In Fig. 8 the neutral or off position of theswitch handle 26 is shown in solid lines, the electrical connectionsbeing open. To start the motor the handle 26 mounted loosely on theshaft 27 is moved to the right into the position indicated in dottedlines and marked start. This movement of the handle 26 to the rightcarries the arm 28 rigidly mounted upon the shaft 27 to the left,because the other end 29 of the handle lever engages with the lug 30 onthe said arm 28. The movable contacts of the switch are controlled bythe shaft 27 in Fig. 8 which corresponds to the shaft 15 in Fig. 2 inits mechanical function. The motor windings are thus connected in starfashion for starting. At the same time the pin 31 movable in the arm 28is lifted by the inclined plane 32 shown in Fig. 7, so that its upperend projects above the surface of the arm 28. As soon as the motor hasreached a proper speed, the switch handle 26 is thrown to the left intothe run position indicated in Fig. 8. If this: movement is made with afair degree of rapidity, the lever 29 catches the projecting end of thepin 31, and the arm 28 is thereby carried to the right. This rotates theshaft 27 which controls the movable contacts and causes them to make thedelta connections for running the motor at full voltage. The pin 31 maybe caught by the lever 29 simply because the former does not have timeto drop out of the way. It may also be temporarily prevented fromdropping by the strip of metal 33 which drips it while the arm 28 isswinging, by reason of the centrifugal force of the mass 34 attached tothe strip 33. Either or both of these means may be employed to catch thepin 31 in order to carry the arm 28 to the right.

In many cases it is desirable to combine my switch with the top or coverof a case or vessel containing oil which serves to suppress the sparkingand arcing that tend to occur on opening electrical connections. In Fig.10 which is a section of such an arrangement of my switch, most of themechanical parts are contained in the upper cover 41, 42. This sets onanother cover 43, 44 which is hinged at 47 on the case 45, 46 containingoil. The electrical parts are attached to the hinged cover 43, 44, andare readily accessible by lifting it. At the same time these electricalcontacts and connections are immersed in the oil when the cover 43, 44is lowered into place. The board 9, 10 in Fig. 10 corresponds to theboard 9, 10 in Fig. l and is moved by the handle 16 to open and closethe electrical connections controlled by the switch. In the constructionshown in Figs. 1 and 10 this movable part 9, 1O simply acts to connecttogether the contacts on the board 1, 2 of Figs. 1 and 10 and has noexternal electrical connections so that it is entirely free to move. Theconnections to the board 1, 2 are made by flexible conductors 48 toenable it to swing upward when the cover 43, 44 is raised. Thisarrangement of the mechanical and electrical parts gives ready access tothem, at the same time they are fully inclosed for protection and may beconveniently immersed in oil or lifted therefrom without disconnectingor disturbing them.

I have shown and described certain forms and uses of my switches whichillustrate their construction, operation and application, but myinvention is not confined to these particular cases. Other mechanicalmeans may be utilized to move and control the contact-making parts so asto effect the proper electrical connections without departing from myinvention. For some purposes only one or a few of its features may beincluded. If desired my switches may be constructed to operate withoutinvolving the sliding of the contact surfaces upon each other, which isherein described as an ad.-

vantageous but not essential feature of my invention. It is evident thatthe stationary element and not the movable element may be constructedwith contact-making parts that yield to pressure, or both may be soconstructed. It is also evident that the movable element may be providedwith electrical connections in the form of flexible or slidingconductors.

With the particular electrical connections illustrated in the drawings,some of the contact-making parts serve in two different positions of theswitch. For example in Fig. 4: the stationary contacts 4 and 7 areconnected to the movable contacts 17 and 19' for running the motor inone direction and to the movable contacts 18 and 20 for running it inthe other direction. It would be possible to have four stationarycontacts for one switch position and four diflerent contacts for theother position, making eight in all.' The arrangement which I have shownpermits two contacts to be used for both switch positions, so that onlysix instead of eight stationary contacts are required. Thus a veryconsiderable gain in simplicity, compactness and cost is made. In otherwords, three sets of contact-making parts are illustrated in Fig. 4. Oneof these sets may be brought into electrical connection with either ofthe other two sets, cor responding to two different switch positions.Each of the three sets may have its own distinct contacts, or some ofthe contacts may be common to two sets, as in Fig. at. In Fig. 4 all ofthe contacts of the movable set are used in both operative switchpositions. In this way various combinations or grou ings in the numberand arrangement of ti? contact-making parts may be made to effeet thedesired electrical connections in the different switch positions,according to the conditions in each case.

In thedrawings I have indicated how various auxiliary features may beincorporated in or used with my switches. For example, they may bearranged with a spring centering device consisting of parts 76, 77, 78,79, 80, 81 and 82 in which the roller 77 is forced against thecam-surface of part 28 so that the switch will open whenever there isnothing to hold it closed. Preferably the switch w1ll be provided with ano-voltage release coil 35 which will after the motor has been properlystarted, hold the switch closed until the no-voltage release coil hasbeen deenergized which will occur when an overload relay operates orwhen the power supply fails or when for convenient stopping, from aremote point,the operator opens the circuit through the no-voltagerelease coil by a push button or switch.

I claim:

1. In an electric switch, the combination of two contact-carryingelements, means for moving about an axis one of said elements withrespect to the other and means movable about an axis for maintainingsaid elements substantially parallel, the axes ofmotion in the two casesbeing substantially at right angles to each other.

2. In an electric switch, the combination of fixed and movablecontact-carrying elements, an arm on which the movable element swingsand a second swinging arm serving to maintain said elementssubstantially parallel.

3. In an electric switch, the combination of fixed and movablecontact-carrying ele ments, an arm on which the movable element swingsabout an axis and a second arm movable about an axis and serving tomaintain said elements substantially parallel, the axes of motion ofsaid arms being substantially at right angles to each other.

Signed by me at Ampere, New Jersey, this sixteenth day of January, 1914.

HAROLD E. WHITE.

FRANCIS B. CRocKER.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

